Search Interview Questions | More than 3000 questions in repository. There are more than 900 unanswered questions. Click here and help us by providing the answer. Have a video suggestion. Click Correct / Improve and please let us know. |
|
| ||||
Interview Questions and Answers for 'Polaris' - 21 question(s) found - Order By Newest | ||||
Frequently asked in Infosys and HCL Technologies ( Based on 2 feedback ) | ||||
| ||||
Ans. Using new operator - new xyzClass() Using factory methods - xyzFactory.getInstance( ) Using newInstance( ) method - (Class.forName(xyzClass))emp.newInstance( ) By cloning an already available object - (xyzClass)obj1.clone( ) | ||||
Sample Code for object initialization using clone Sample Code for object initialization using getInstance | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   oops   object creation   new operator   class.forname   cloning   ebay Asked in 9 Companies expert | ||||
Basic and Very Frequently asked. | ||||
| ||||
Ans. Polymorphism means the condition of occurring in several different forms. Polymorphism in Java is achieved in two manners 1. Static polymorphism is the polymorphic resolution identified at compile time and is achieved through function overloading whereas 2. Dynamic polymorphism is the polymorphic resolution identified at runtime and is achieved through method overriding. | ||||
Sample Code for overloading Sample Code for overriding | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  polymorphism  object oriented programming (oops)  oops concepts  oops concepts Asked in 108 Companies Basic   frequent | ||||
Try 2 Question(s) Test | ||||
Very Frequently asked. Have been asked in HCL Technologies very frequently ( based on 3 feedback ). Among first few questions in many interviews. | ||||
| ||||
Ans. Abstract classes can have both abstract methods ( method declarations ) as well as concrete methods ( inherited to the derived classes ) whereas Interfaces can only have abstract methods ( method declarations ). A class can extend single abstract class whereas it can implement multiple interfaces. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   classes   abstract class   interfaces   abstract class vs interface   abstract classes vs interfaces Asked in 82 Companies basic   frequent | ||||
| ||||
Ans. abstract and final | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   java keywords Asked in 2 Companies basic | ||||
Frequently asked in Infosys India | ||||
| ||||
Ans. String pool (String intern pool) is a special storage area in Java heap. When a string is created and if the string already exists in the pool, the reference of the existing string will be returned, instead of creating a new object and returning its reference. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   oops   string   string class   string pool   heap memory Asked in 31 Companies intermediate   frequent | ||||
Try 2 Question(s) Test | ||||
Very Frequently asked to fresh graduates and less experienced. Favorite question in Walk in drives. Frequently asked in Indian Services companies. | ||||
| ||||
Ans. Overloading - Similar Signature but different definition , like function overloading. Overriding - Overriding the Definition of base class in the derived class. | ||||
Sample Code for overloading Sample Code for overriding | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   oops   overloading   overriding   oops concepts   basic interview question   overloading vs overriding Asked in 86 Companies basic   frequent | ||||
Try 1 Question(s) Test | ||||
| ||||
Ans. JDK(Java Development kit) = Development Kit comprising of JVM , library and development tools for developers JRE (Java Run time Environment) - Comprise of JVM and set of libraries JVM(Java Virtual Machine) = Interpreter which reads the .class file line by line. When we install JDK, JRE also get installed so we can write,compile and excute our code. Used by developer. Without JDK we can only execute the program using JRE. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  jvm  jre  jdk  jvm vs jre vs jdk Asked in 4 Companies | ||||
Frequently asked in high end product companies. Frequently asked in Deloitte. | ||||
| ||||
Ans. https://medium.com/javarevisited/internal-working-of-hashmap-in-java-97aeac3c7beb#:~:text=HashMap%20internally%20uses%20HashTable%20implementation,the%20entries%20into%20the%20map. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  hashmap  collections  hashmap internal implementation Asked in 20 Companies expert   frequent | ||||
| ||||
Ans. Generalization or UpCasting is a phenomenon where a sub class is prompted to a super class, and hence becomes more general. Generalization needs widening or up-casting. Specialization or DownCasting is a phenomenon where a super class is narrowed down to a sub class. Specialization needs narrowing or down-casting. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   data types   casting  type casting   up casting  type casting   downcasting  type casting   generalization   specialization Asked in 2 Companies | ||||
Frequently asked in CTS ( Based on 2 feedback ) | ||||
| ||||
Ans. Comparable interface is used for single sequence sorting i.e.sorting the objects based on single data member where as comparator interface is used to sort the object based on multiple data members. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   java.util   comparable   comparator   collections Asked in 23 Companies basic   frequent | ||||
| ||||
Ans. intern() method keeps the string in an internal cache that is usually not garbage collected. Moreover provide reference for scp object for corresponding string object present in heap memory. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   string class   string   intern method   garbage collection   advanced Asked in 2 Companies expert | ||||
| ||||
Ans. Abstraction is a process of hiding the implementation details and describing only the functionality to the user. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  bstraction  oops concepts  oops principle Asked in 22 Companies | ||||
| ||||
Ans. A class is a blue print or Mold using which individual objects are created. A class can contain fields and methods to describe the behavior of an object. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   oops   class   basic interview question Asked in 1 Companies basic   frequent | ||||
| ||||
Ans. Hashcode is used for bucketing in Hash implementations like HashMap, HashTable, HashSet etc. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   string   hashcode   hash code   string comparison  hashtable Asked in 17 Companies basic   frequent | ||||
| ||||
Ans. No, results in exception. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   collections   treemap Asked in 6 Companies Basic   frequent | ||||
Frequently asked in face to face interviews. | ||||
| ||||
Ans. int count = 15; int[] fibonacci = new int[count]; fibonacci[0] = 0; fibonacci[1] = 1; for(int x=2; x < count; x++){ fibonacci[x] = fibonacci[x-1] + fibonacci[x-2]; } for(int x=0; x< count; x++){ System.out.print(fibonacci[x] + " "); } | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  ebay   fibonacci series Asked in 66 Companies basic   frequent | ||||
| ||||
Ans. Abstract means that the class is only meant to be subclassed whereas final means that it cannot be subclassed so both concepts - abstract and final are actually mutually exclusive and hence not permitted together. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  abstract   final   java keywords Asked in 1 Companies | ||||
| ||||
Ans. Abstract classes provide a mechanism of interfacing ( using abstract method ) as well as inheritance ( extending abstract class ). So they should be used in place of interfaces in case there is some code ( methods ) or object body ( member elements ) that can be reused with inheritance. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  abstract classes Asked in 1 Companies | ||||
| ||||
Ans. Yes, it will compile without error. final in this context means that the reference hm cannot be assigned to a new hash map but didn't restrict from changing the state of collection already held by hm. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  final  final variable Asked in 1 Companies | ||||
| ||||
This question was recently asked at 'Polaris'.This question is still unanswered. Can you please provide an answer. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  memory leak Asked in 1 Companies | ||||
| ||||
This question was recently asked at 'Polaris'.This question is still unanswered. Can you please provide an answer. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve   Asked in 1 Companies | ||||